The symbolic ceremony was exactly like a legal ceremony. Many of our guests didn't know we were legally married at home before we left and no one noticed a difference. You still say vows, they still pronounce you "man and wife", you and your witnesses still sign a certificate and it still feels just as special as a legal ceremony would. The only thing was that it was very short (6 minutes!) which was fine for us since our guests were sitting in the hot sun and we were eager to get on with the party! If you'd like any special readings or vows make sure you bring them with you and give them to your WC to be included in the ceremony.
We paid for everything upon checkout. I had made a list of everything that I expected to be charged for so I had an idea of what the total should be and the total they provided was pretty close to that so we didn't bother to ask for an itemized bill. Keep in mind that they give you the total in pesos so be ready for a quick conversion (generally 10 pesos per dollar).
Hope that helps!